The ball-related sports have covered a wide variety of body physical exercising forms, including running, jumping and throwing etc. In addition, they have a relatively high exercising intensity. Therefore, they can promote physical fitness and overall developments of the human body functions in a comprehensive, effective and integrated manner, improve and maintain people's vitality, and provide a solid body (substance) basis for all different types of human activities. Hence they will improve people's living quality. There are many different balls available on the market, so it is very important to choose a high quality ball. This is so that when in use, a person may feel quite comfortable when grabbing a high quality ball. Moreover, a ball with stable bouncing and rotating performance would be helpful for developing good dribbling habits, as well as to perform standard technical abilities well. A ball of excellent quality can also enhance its user's self-confidence, improve the quality of training and bring more fun to the exercises. Further, a high quality ball will have a longer service life.
The sports ball can be divided into rubber (plastic) balls, hand-sewn or machine-sewn balls, and laminated balls. The most commonly used ball is the laminated basketball. It is comprised of an inner body layer, a sheath layer, a ball opening and so on. The inner body layer is the inner ball bladder, which is the heart of the ball and located at the innermost layer of the ball. It is made of black-colored rubber. The quality of air tightness of the inner bladder determines the service life of the ball. Although the air tightness quality of the traditional ball is fairly good, it is still prone to leaks following a long period of use. Document U.S. Pat. No. 2,623,747 describes an inflatable athletic ball.